Several types of converters are known for use in power supply systems, where there is a need to convert an AC power to a controlled DC power. The AC power will usually be supplied from an AC power source, such as the mains. The DC power is supplied to equipment such as telecommunication equipment, broad band data communication equipment (GSM/UMTS base stations etc), military equipment, medical equipment etc.
There are several requirements for such power supply systems. First of all, the efficiency should be high, i.e. the losses should be low. The power supply system described in WO 2009/028954 and WO 2009/058024 has an efficiency of ca 96% and is marketed and sold by Eltek Valere under the name FlatPack 2 HE. The power supply system provided as a unit for insertion into a rack. The unit has an height of 1U (the standard height of one shelf in a rack, corresponding to 44.5 mm), a length of 328 mm and a width of 109 mm so that four such units may be provided next to each other in a 19″ rack. The unit may deliver a power of 2 kW or 3 kW at −48V DC.
The object of the next generation power supply is to provide a smaller unit having substantially the same power as the above power supply system and with a relatively high efficiency. More specifically, the new unit should be 1U high. The length should be 220 mm so that the unit and the rack may be provided in a 30 cm power cabinet. In addition, the width should 72 mm in order to provide that six such units may be provided next to each other in a 19″ rack. The unit should be able to supply a power of 2-3000 W at −48V DC. Hence, the available volume for the components is reduced by approximately 55%.
Another important object of the next generation power supply system is to reduce costs. One contribution to cost reduction is the reduced size. Another contribution to cost reduction is to use cheaper electronic components such as processor units etc. However, such electronic components are simpler, and consequently, effort must be put into using the electronic components smarter. One way of achieving this is to reduce the number of calculations needed for controlling the power supply system.
A safety requirement for the power converting unit is that it needs to be locked to the rack, and a tool must be needed to unlock the unit from the rack.
Hence, the object of the invention is to provide a power supply system comprising a power converter unit and a rack, where the unit can be releasably locked to the rack and where the locking mechanism does not occupy valuable space from the electronic components and other components of the power supply system. Hence, the object of the invention is to make it possible to provide a power supply unit with the specifications mentioned above.